This research program is directed toward the understanding and evaluation of personal health care services. Its objective is to describe needs, demands, utilization, outcomes, organization and financing of health care services provided in group practices, hospitals, physicians' offices, clinics, health departments and health centers. It is concerned also with planning of effective, economical health services. Epidemiologic principles and survey techniques are used, in addition to the development of greater uniformity in definitions, greater standardization of data, and new information systems. As far as possible, defined populations are used as the basis of study. Special attention is given to developing methods and criteria for relating costs and benefits of health services. Studies include international comparisons of health services utilization and satisfaction of patients. All of these studies are carried out by a group of full-time investigators committed to health services research and development.